Abstract: In response to the demand for real-time and accurate tracking of multiple surgical instruments in collaborative operations, this study aims to solve the problem of invisible instrument ends caused by light filtering and shielding based on a near-infrared active optical tracking system, and achieve accurate identification and stable tracking of multiple surgical instruments. The problem of surgical instrument tracking based on a near- infrared optical positioning system is explored. In response to the limitations of traditional algorithms in multi- instrument recognition and landmark tracking, a multi-instrument recognition method based on point set matching is proposed. By matching the landmark points in the captured image with the pre-established instrument model, accurate identification and differentiation of multiple surgical instruments are achieved. And a landmark tracking method based on least squares algorithm prediction is proposed. The historical tracking data and the least squares method are used to predict the location of the landmark points, thereby achieving real-time tracking of surgical instruments. Experimental verification shows that the coordinated use of the two methods can achieve accurate identification (first-frame recognition rate 100% ) and stable tracking (overall recognition rate 97. 45%) of multiple surgical instruments, while ensuring tracking accuracy and meeting the real-time requirements of surgery. It can provide surgeons with clear instrument spatial position information and support precise operations. It is of great significance to improving surgical safety and reliability, and can provide technical support for the clinical application of near-infrared optical surgical navigation systems.

Key words: optical positioning, multiple surgical instrument recognition, point set matching